While there is a myriad of art covering laser mirrors (e.g., U.S. Pat. Nos. 3,836,236; 3,926,510; and 3,942,880) because of the many peculiar physical property requirements of such mirrors in this environment, both a variety of materials and designs have been employed in attempts to optimize the particular properties necessary for a composite used in this particular environment. For example, while a laser mirror in this environment must have the requisite reflective properties, cost and availability of materials as well as ease of fabrication are also important factors. Such mirrors should also desirably have low density for ease of use in the types of apparatus where they will be used, but without porosity. Furthermore, such mirrors ideally should have high elastic stiffness and high strength along with high fracture toughness. And stability is of the utmost importance both from the point of view of the fine resolution-type work environment the mirrors will be used in, and the inaccessibility of the apparatus which these mirrors would be used in, for example, outer space applications. These stability properties includes low thermal expansion, high thermal conductivity, and environmental stability. Environmental stability includes such things as dimensional stability and mirror integrity regardless of moisture conditions, vacuum conditions, or ultraviolet light exposure, and mirror integrity and dimensionally stability at both high and low temperatures. Currently, laser mirrors are basically either highly polished metal blocks (high energy laser application) or graphite reinforced resin matrix composites (low energy laser application). However, currently used composites fall off in one or more of the above-cited property areas. Furthermore, the popular use of resins in conventional composites of the above type inherently suffer from dimensional changes due to absorption or desorption of moisture, evolution of organic constituents due to prolonged exposure to high vacuum, breakdown due to prolonged exposure to ultraviolet radiation, low thermal conductivity, high coefficients of thermal expansion, and rapid decrease in integrity when used above 300.degree. C. And while cooling channels have been provided in such mirrors in an attempt to achieve some of the above-cited property goals, relatively complicated manufacturing procedures have been necessary to produce such artilces and still the coefficients of thermal expansion, thermal stability, and integrity of the mirrors produced have not been totally satisfactory from the point of view of mirror properties and duration of use. Furthermore, because of the limitations imposed by the use of conventional laser mirror materials, design options for cooling channel shapes is limited.